1. Field of the Invention
This invention relates to a method of making embossed or contoured articles or materials, such as quilted or embossed fabrics as used for example in upholstery, or pre-shaped panels or cushions used for example for lining the interior or motor vehicles, or articles such as saddles, footwear etc., or again in upholstery. Normally, such articles or materials are of a laminated construction with a facing layer on one side of a relatively soft filler layer and usually, but not necessarily, a backing layer on the other side. The filler layer may be formed from a foamed plastics material or a fibrous material such as wadding, felt or other absorbent material.
2. Description of the Prior Art
Previously known methods of forming such materials and articles can be divided broadly into two categories which may be called `passive or mechanical` processes on the one hand and `active or chemical` processes on the other hand.
The `passive` processes are characterised by the use of pre-formed materials which are simply formed into a laminate and embossed or shaped by operations which can usually be carried out by the user of the materials and articles thus formed. Thus the user can make use of commercially available stock materials and form shaped materials and articles according to his own production requirements.
The `passive` processes include methods whereby laminated materials of relatively small thickness are formed essentially by securing the several layers together at appropriate positions, either mechanically (e.g. by stitching) or by heat sealing as for example disclosed in U.S. Pat. No. 3,170,832. In such cases, the shape of the embossed pattern is determined by the attachment of the layers over only a very small fraction of the total surface area of the material. The foamed material or other soft material which forms the filler is maintained in a compressed condition in and around such secured areas solely by the attachment of the layers to one another and this limits the depth of pattern that can satisfactorily be embossed, whilst in heat sealing when a foamed material is employed the foamed structure of the material may be destroyed where the sealing takes place, and the facing layer may become glazed.
The `active` processes are characterised by the use of chemical polymerisation techniques for forming the filler material, or at least a part thereof, in-situ, and to the required shape. These processes can normally only be carried out by the manufacturers of synthetic polymers under very carefully controlled conditions and not by the manufacturers who wish to use the shaped materials and articles thereby produced in the manufacture of their own products.
In one example of such an `active process`, as described in U.S. Pat. No. 2,855,021, shaped articles of foamed plastics materials are formed by allowing the foaming of the plastics material to take place in a suitably shaped die. However, this process requires very expensive dies and involves the use of hazardous chemicals.
An example of a further `active` process for making embossed laminated materials is described in U.S. Pat. No. 3,256,131. This discloses the use of a foam forming plastics material as a bonding agent for facing layers and a filler of foamed plastics material. The foam forming material is applied to the surfaces of the layers to be bonded together and foaming takes place when the layers are in contact with one another. The foam produced penetrates the cells of the foamed plastics material and causes the facing layer to adhere thereto. If the laminated material is contacted by an embossing die so that the facing layers are substantially brought together until the foaming material is cured, the laminate is thereby formed with an embossed pattern and the shaping of the foamed material is maintained by adhesive of the facing layers. However, this method again utilises hazardous chemicals and is relatively difficult to control since the foam forming material must be applied in carefully monitored quantities. Also this method is only applicable to the manufacture of laminated materials in which a foamed plastics filler material has facing layers thereon. Additionally, the foaming process must be carried out at an elevated temperature and this imposes limits on the material which may be employed as the facing layer.